Carbon/carbon (“C/C”) parts are employed in various industries. An exemplary use for C/C parts includes using them as friction disks such as aircraft brake disks, race car brake disks, clutch disks, and the like. C/C brake disks are especially useful in such applications because of the superior high temperature characteristics of C/C material. In particular, the C/C material used in C/C parts is a good conductor of heat, and thus, is able to dissipate heat away from the braking surfaces that is generated in response to braking. C/C material is also highly resistant to heat damage, and is capable of sustaining friction between brake surfaces during severe braking, without a significant reduction in the friction coefficient or mechanical failure.
Today's prevalent commercial approach to prepare fibrous preform structures for manufacturing carbon-carbon brake disks is to needle-punch layers of OPF PAN fibers in a board shape from which donut shape preforms are cut. The preforms are subsequently subjected to a costly carbonization cycle to transform the fiber into carbon. This approach yields a large amount of fiber waste. A more effective method to fabricate the fibrous preform structure is to organize carbonized fibers with a suitable fiber architecture in a continuous handleable spiral shape fabric. The carbon fiber narrow fabric is subsequently fed into a circular needle punch machine to prepare a three dimensional textile.
Various technologies exist for fabricating a continuous spiral fabric by modifying a conventional weaving loom such as a rapier or shuttle loom. Conical take-off rollers are used to control the take-up advance of the various warp yarns to form the specific geometry of the spiral fabric. The shuttle loom offers some weave architecture flexibility but does not allow a seamless continuous process as it requires costly repackaging of the yarn. Thus, weaving with a shuttle loom is generally highly inefficient.
Rapier loom technology also has undesirable limitations. For example rapier looms generally transport the weft fibers across the full width of the fabric. This type of weaving may result in non-uniformity of the fiber spacing at various circumferences across the radius of a spiral textile. In this regard, spiral-shaped textiles prepared with weft fibers that solely extend across the entire width of the textile tape generally exhibit a deficiency in that the density of the weft fibers decreases moving from the inside diameter of the spiral-shaped textile to the outside diameter of the textile (i.e., in the radial direction).
For example, with reference to FIG. 1, a prior art spiral-shaped textile is illustrated. Because the number of weft fibers extending from the inner diameter or second edge of the textile to the outer diameter or first edge of the textile is the same, the radial fiber content (δ) is lower at the outer diameter (δOD) than the radial fiber content at the inner diameter (δID). Stated another way, the concentration of the weft fibers, or the weft fiber density, at the inner diameter is greater than the concentration of the weft fibers at the outer diameter because the circumference at the inner diameter is shorter than the circumference at the outer diameter, but the same number of weft fibers are present at both circumferences. Such a fiber architecture may result in a number of shortcomings during subsequent processing and in the mechanical and thermal properties of the final product.
The formation of continuous spiral and/or helical fabrics using conventional weaving looms and conical take up rollers has been pursued due to an interest in carbon and ceramic fiber textiles with fibers oriented in radial and circumferential orientations to prepare donut shape components like turbine rotors.
Current methods for fabricating a continuous helical fabric with suitable fiber orientation for brake applications or other thermo-structural applications are not economical because they typically employ a shuttle loom to weave the helical fabric. In a shuttle loom (see, e.g., FIGS. 2A-2B), the shuttle transports the continuous weft yarn through the open shed from a so called starting warp yarn defining the outer circumference of the helical fabric. The formation of the subsequent shed is designed to allow looping the same weft yarn around a selected so-called reference warp yarn during the return of the shuttle to its starting position. This technology is inherently slow and poorly adapted to large scale and/or mass production of narrow helical fabrics. Shuttle looms are designed for weaving of broad goods, and may only accommodate the fabrication of one helical tape at a time. Furthermore one drawback of a shuttle loom is that small amounts of yarn need to be repackaged on special bobbins or quills which fit in the shuttle. This technology also has upper limits on yarn size, which further negatively affects weaving speed. The larger the tow the more fiber damage takes place during winding and un-winding of the tow to and from the shuttle bobbin, so the shuttle technology is generally limited to weft carbon tows no larger than 12 K.
Newer weaving technology such as narrow fabric needle looms are capable of operating at very high speed thanks to a short travel of the weft insertion device and the effective introduction of two weft yarn segments of the same weft yarn at each weft needle insertion. These looms typically equipped with one weft needle are generally use to manufacture narrow straight fabrics with low denier yarns such as ribbons and are not configured for manufacturing spiral-shaped textiles or handling larger yarn in the weft direction.
Moreover, certain narrow fabric needle looms have two or more needles configured to introduce weft yarns in separate sheds, thus creating pockets across the width of the tape. However, these multiple needles are configured to dispose the weft yarns over a fixed length across the width of the textile.
A circular needle-punching loom may be utilized to form a circular preform from spiral textiles, for example, for use in creating carbon brake disks. Various textile technologies exist for fabricating a continuous carbon feed form for a circular needle loom, including yarn placement, stitch bonding, pre-needling, and conventional loom weaving with conical take-up rolls. Narrow fabric needle looms, with suitable modification to transport larger textile tows in the weft direction and with an alternate take-off system, may be utilized to produce a continuous spiral textile tape to be utilized in a circular needle-punching loom to form a circular preform. These spiral textiles may contain warp fibers which lie along the length of the textile, and weft fibers which lie along the width of the textile.
Significantly, some prior art mechanisms and methods for transporting a spiral textile from a loom (where the textile is woven) to a circular needle-punching loom require much more space in order to deliver the spiral textile in a complex path to the circular needle loom. This complex path is utilized in order to maintain the weave and overall shape of a spiral textile from the time it leaves the fabric needle loom to the time it is deposited in the circular needle loom. For example, the spiral textile may by layered horizontally on a vertical spool from the weaving loom as illustrated in FIG. 3, such that it is removed from the spool and oriented to be disposed horizontally on a circular needle loom. As can be appreciated, such a configuration requires that the textile tape change directions from the spool to the circular needle loom, resulting in a circuitous path from the spool to the loom. Further, unwinding the spiral fabric from the horizontal plane on the top layer of the vertical spool to the horizontal plane of the circular needle loom may be challenging.
Accordingly, there is a need for developing an economical technology to manufacture, on a large scale, a narrow fabric product in the form of a continuous helical tape constructed with carbon, ceramic and/or other fibers. Furthermore, a fiber architecture is desirable that has a reasonable homogeneous fiber content across the fabric width to facilitate further processing and to yield suitable properties. Additionally, a reasonably consistent thickness of the fabric across the textile width is desirable during needle punching. In the case of a carbon brake disk application, it may be desirable to obtain a higher ratio of radial to circumferential reinforcement to draw out heat along the radial direction, thus a fabric with a higher weft to warp fiber content may be desirable.
Furthermore, it is desirable to develop a narrow fabric needle loom for producing spiral-shaped textiles which are capable of providing a more consistent radial fiber content across the radius of the spiral-shaped textile. Additionally, it is desirable to develop a loom with one or multiple needles that are configured to dispose weft yarns of variable lengths across the width of the textile. Further still, it is desirable to develop a system and method for manufacturing a continuous carbon feed form at a higher manufacturing speed.
Moreover, it is desirable to provide a mechanism and method to efficiently collect the spiral fabric from a weaving station, transport it to a circular needle loom and continuously feed the spiral fabric to the bed plate of the circular needle loom. It is further desirable to reduce the amount of space used to transport the spiral textile. Additionally, it is desirable to transport the spiral textile tape while reducing distortions in the weave of the spiral textile that are generated in existing spiral textile transport mechanisms.